TY - GEN A1 - Kramm, Ulrike Ingrid A1 - Lefèvre, Michel A1 - Bogdanoff, Peter A1 - Schmeißer, Dieter A1 - Dodelet, Jean-Pol T1 - Analyzing Structural Changes of Fe-N-C Cathode Catalysts in PEM Fuel Cell by Mößbauer Spectroscopy of Complete Membrane-Electrode-Assemblies T2 - The Journal of Physical Chemistry Letters N2 - The applicability of analyzing by Mößbauer spectroscopy the structural changes of Fe–N–C catalysts that have been tested at the cathode of membrane electrode assemblies in proton exchange membrane (PEM) fuel cells is demonstrated. The Mößbauer characterization of powders of the same catalysts was recently described in our previous publication. A possible change of the iron species upon testing in fuel cell was investigated here by Mößbauer spectroscopy, energy-dispersive X-ray cross-sectional imaging, and neutron activation analysis. Our results show that the absorption probability of γ rays by the iron nuclei in Fe–N–C is strongly affected by the presence of Nafion and water content. A detailed investigation of the effect of an oxidizing treatment (1.2 V) of the non-noble cathode in PEM fuel cell indicates that the observed activity decay is mainly attributable to carbon oxidation causing a leaching of active iron sites hosted in the carbon matrix. KW - iron-based catalyst KW - iron−nitrogen−carbon catalyst KW - non-noble metal catalyst KW - nonprecious metal catalyst KW - oxygen reduction reaction KW - ORR KW - polymer electrolyte membrane fuel cell KW - PEM-FC KW - degradation Y1 - 2014 U6 - https://doi.org/10.1021/jz501955g SN - 1948-7185 VL - 2014 IS - 5 SP - 3750 EP - 3756 ER - TY - GEN A1 - Indra, Arindam A1 - Menezes, Prashanth W. A1 - Sahraie, Nastaran Ranjbar A1 - Bergmann, Arno A1 - Das, Chittaranjan A1 - Tallarida, Massimo A1 - Schmeißer, Dieter A1 - Strasser, Peter A1 - Driess, Matthias T1 - Unification of Catalytic Water Oxidation and Oxygen Reduction Reactions: Amorphous Beat Crystalline Cobalt Iron Oxides T2 - Journal of the American Chemical Society N2 - Catalytic water splitting to hydrogen and oxygen is considered as one of the convenient routes for the sustainable energy conversion. Bifunctional catalysts for the electrocatalytic oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are pivotal for the energy conversion and storage, and alternatively, the photochemical water oxidation in biomimetic fashion is also considered as the most useful way to convert solar energy into chemical energy. Here we present a facile solvothermal route to control the synthesis of amorphous and crystalline cobalt iron oxides by controlling the crystallinity of the materials with changing solvent and reaction time and further utilize these materials as multifunctional catalysts for the unification of photochemical and electrochemical water oxidation as well as for the oxygen reduction reaction. Notably, the amorphous cobalt iron oxide produces superior catalytic activity over the crystalline one under photochemical and electrochemical water oxidation and oxygen reduction conditions. KW - photochemical KW - electrochemical KW - catalyst KW - water oxidation reaction KW - oxygen reduction reaction KW - cobalt iron oxides KW - control of crytallinity Y1 - 2014 U6 - https://doi.org/10.1021/ja509348t SN - 1520-5126 SN - 0002-7863 VL - 2014 IS - 136 SP - 17530 EP - 17536 ER - TY - CHAP A1 - Narra, Satyanarayana A1 - Logsch, Florian A1 - Glaser, Claudia A1 - Ay, Peter A1 - Döhling, Frank A1 - Leistner, Diana A1 - Strube, Dieter ED - Thrän, Daniela ED - Pfeiffer, Diana T1 - LignoBioFuel : Entwicklung eines Verfahrens zur Herstellung von stofflich und energetisch nutzbaren Bioagglomeraten auf der Basis von Lignin T2 - Effizient, umweltverträglich, dezentral - neue Konzepte für die Nutzung von biogenen Festbrennstoffen, Bd. 2 Y1 - 2014 SP - 85 EP - 99 PB - DBFZ, Dt. Biomasseforschungszentrum CY - Leipzig ER - TY - CHAP A1 - Seifarth, Olaf A1 - Walczyk, Christian A1 - Lupina, Grzegorz A1 - Zaumseil, Peter A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim A1 - Schroeder, Thomas T1 - The electronic band diagram of thin PrO2(111) / Pr-silicate buffers on Si(111) and its relevance to dielectric properties T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 44 N2 - Thin dielectric buffers of cubic PrO2(111) on Si(111) are ideally suited to integrate Ge onto Si by moderating the lattice mismatch between the materials. The leakage current across this dielectric buffer is strongly influenced by the electronic band diagram and defects inside the band gap. Therefore, we measured the band offsets, band gaps and defect positions by means of synchrotron radiation based photoemission spectroscopy techniques (XPS and XAS) with special emphasis on the Pr-silicate interface. In a next step we compare the spectroscopic data with information from dielectric studies, based on temperature dependent leakage current studies. We observe a close relation between dielectric properties and the electronic structure. Y1 - 2009 UR - http://www.dpg-verhandlungen.de/year/2009/conference/dresden/part/df/session/6/contribution/5 SN - 0420-0195 SP - S. 136 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Dudek, Peter A1 - Lupina, Grzegorz A1 - Kozłowski, Grzegorz A1 - Dabrowski, Jarek Marek A1 - Lippert, Gunther A1 - Müssig, Hans-Joachim A1 - Schmeißer, Dieter A1 - Schroeder, Thomas T1 - Band structure and electrical properties of MBE grown HfO2 - based alkaline earth perovskites T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45 N2 - Ultra thin dielectric films (<20 nm) deposited on TiN electrodes are interesting for MIM capacitor application. High capacitance density and dielectric permittivity must be accompanied by extremely low leakage currents (10−8 A/cm2) at bias 0.5 V. To achieve such low leakage currents, high band gap and proper band alignment is required. Occupied electronic states can be probed with standard laboratory photoemission methods. Probing of unoccupied states is more challenging. Synchrotron based PES in combination with XAS forms a powerful method to study the band alignment. ASAM end station located at the U 49/2 PGM 2 beamline of BESSY II (Berlin) offers excellent conditions for performing such measurements. We investigated HfO2 - based alkaline earth perovskite - BaHfO3 with subsequent admixture of TiO2, resulting in formation of BaHf0.5Ti0.5O3 compound. The analysis of data indicates that band gap for HfO2 is similar to BaHfO3 and amounts 5.8 eV; for BaHf0.5Ti0.5O3 it decreases to 3.8 eV. We conclude that the addition of TiO2 to BaHfO3 increases significantly the dielectric permittivity but also impacts the band gap alignment. The conduction band offset shrinks, influencing the leakage current behavior. Y1 - 2010 UR - http://www.dpg-verhandlungen.de/year/2010/conference/regensburg/part/ds/session/24/contribution/4 SN - 0420-0195 SP - S. 232 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Pöhlmann, Fiete A1 - Bestle, Dieter A1 - Flassig, Peter Michael A1 - Hinz, Michèl ED - Greiner, David ED - Galvàn, Blas ED - Pèriaux, Jacques ED - Gauger, Nicolas R. ED - Giannakoglou, Kyriakos C. ED - Winter, Gabriel T1 - Modular Automated Aerodynamic Compressor Design Process T2 - Advances in Evolutionary and Deterministic Methods for Design, Optimiziation and Control in Engineering and Sciences KW - Multi-criterion optimization, Compressor design, Multi-fidelity processes, Process coupling, Meanline, Throughflow, Blading Y1 - 2015 SN - 978-3-319-11540-5 SN - 978-3-319-11541-2 U6 - https://doi.org/10.1007/978-3-319-11541-2 SP - 267 EP - 276 PB - Springer CY - Cham ER - TY - CHAP A1 - Goryachko, Andriy A1 - Beuckert, Guido A1 - Zaumseil, Peter A1 - Wagner, Guenter A1 - Schmeißer, Dieter T1 - Investigations of Pr2O3 growth modes on 4H-SiC(0001) Surfaces T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - The SiC is suited especially well for high power and high voltage semiconductor devices. In order to increase the reliability against electrical breakdown of metal-insulator-semiconductor (MIS) structures, one needs to use the insulator with possibly higher dielectric constant. Pr2O3 is shown to posses a much higher dielectric constant (equals 30) than traditionally used SiO2. Therefore, Pr2O3/SiC is an excellent material combination for high voltage MIS devices. The 4H-SiC(0001) substrates are characterised with scanning tunneling microscopy, while the Pr2O3 surface - with atomic force microscopy technique. We show distinct growth modes of Pr2O3 film, such as 3D and layer by layer growth. The crystalline structure and film thickness are determined by X-ray diffraction and its chemical composition by X-ray photoelectron spectroscopy. The Pr2O3 film characteristics are optimised for high-quality MIS structures in terms of lateral uniformity, low interface states density and leakage current, as well as physical integrity. KW - SiC KW - Pr2O3 KW - X-ray photoelectron spectroscopy (XPS) KW - X-Ray diffraction Y1 - 2004 UR - http://www.dpg-verhandlungen.de/year/2004/conference/regensburg/part/ds/session/9/contribution/4?lang=de SN - ISSN 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Hendler, Marco A1 - Extra, Simon A1 - Lockan, Michael A1 - Bestle, Dieter A1 - Flassig, Peter Michael T1 - Compressor Design in the Context of Holistic Aero Engine Design T2 - 2017 AIAA Aviation Forum, Denver, AIAA-2017-3334, 2017 KW - Holistic Optimization KW - Aero Engines KW - Computational Fluid Dynamics Y1 - 2017 U6 - https://doi.org/10.2514/6.2017-3334 ER - TY - GEN A1 - Lutter, Anne-Helen A1 - Hempel, Ute A1 - Anderer, Ursula A1 - Dieter, Peter T1 - Biphasic influence of PGE2 on the resorption activity of osteoclast-like cells derived from human peripheral blood monocytes and mouse RAW264.7 T2 - Prostaglandins, Leukotrienes and Essential Fatty Acids KW - osteoclastic differentiation Y1 - 2016 U6 - https://doi.org/10.1016/j.plefa.2016.03.017 SN - 1532-2823 SN - 0952-3278 VL - 111 SP - 1 EP - 7 ER - TY - GEN A1 - Lutter, Anne-Helen A1 - Hempel, Ute A1 - Dieter, Peter A1 - Anderer, Ursula T1 - Multinuclearity is not mandatory for Bone Resorption Mononuclear Osteoclasts are able to resorbe Extracellular Bone Matrix in vitro T2 - Bone-Tec, Munich, 2017 KW - mononuclear osteoclast Y1 - 2017 UR - https://www.researchgate.net/publication/327860900 ER -